17 November 2000

Vigilance thwarts spud storage breakdowns

By Louise Impey

POTATO growers must be extra vigilant to prevent storage breakdowns this season. Grading out rots, curing carefully, keeping crops cool and monitoring stores daily will be vital.

"If growers do nothing else they should grade out rots before loading," says Farmacy agronomist Mark Taplin. "Missing a few greens and misshapen tubers is not a big issue, but missing rots is a disaster."

Agressive cleaning

More aggressive cleaning will also help. "That may mean more damage, but the aim must be to get crops as clean as possible."

Growers who have loaded most of the crop into store, despite the rain, must take every opportunity to ventilate and minimise condensation, he advises. Temperatures must be kept stable.

A good strategy is to lengthen curing and use cooler temperatures. "Bacterial activity is less at lower temperatures, so check store fans and louvres are working and keep looking for signs of deterioration.

"Things can happen very quickly, so growers should be in the store every day. Tubers have gone in wetter and there will have been some skin damage at lifting. Erupted lenticels are also a feature of the very wet season and will allow disease to spread."

The main disease pressure is from bacterial soft rots and blight. "Blackleg was around in crops during the growing season and pink rot is important locally, but wont necessarily be a national problem."

Crops still in the ground are unlikely to suit long-term storage, especially for processing markets. "Fry colours are affected as soil temperatures fall. And there are opportunities to move crop now, so it may be best to forget about storage where theres been a delay."

Over-wintering crops in the field can work, he adds. "Provided it does not flood or freeze, crops do not necessarily suffer too much. But it is very soil dependent."

Avoiding potato breakdown in store demands rigorous attention to detail, agree Staffs grower Steven McKendrick (left) and Farmacys Mark Taplin.

STORAGETIPS

&#8226 Wet, dirty, damaged crops.

&#8226 Late maturity skin set issue.

&#8226 Use longer, cooler curing.

&#8226 Dry thoroughly.

&#8226 Minimise condensation.

&#8226 Grade rots out at intake.

&#8226 Minimise and check bruising.

&#8226 Over-winter in-field?